<!DOCTYPE html>
<html>
<head>
  <title>Destroy and Hide Element in Animation Event</title>
  <!-- Note: this is effectively a crashtest, but as crashtests do not
       support variants, authoring as a promise test -->
  <meta name="variant" content="?animationstart">
  <meta name="variant" content="?animationiteration">
  <link rel="help" href="https://bugs.webkit.org/show_bug.cgi?id=22635">
  <style>
    .box {
      height: 100px;
      width: 100px;
      margin: 10px;
      background-color: blue;
      /* Use a long duration and delay for precise control over when animation
         events are triggered. With short animations, the animation-iteration
         event could be dropped if the animation finishes too son. An
         animation-iteration event does not fire when completing the last
         iteration.
      */
      animation-name: move;
      animation-duration: 10000s;
      animation-delay: 5000s;
      animation-iteration-count: 2;
    }

    @keyframes move {
      from { transform: translate(0px, 0px); }
      to { transform: translate(100px, 0px); }
    }
  </style>
  <div id="container">
    <div id="box1" class="box"></div>
    <div id="box2" class="box"></div>
  </div>
  <script src="/resources/testharness.js"></script>
  <script src="/resources/testharnessreport.js"></script>
  <script src="/common/gc.js"></script>
  <script>
  'use strict';

  function eventPromise(target, event, callback) {
    return new Promise(resolve => {
      const listener = () => {
        callback();
        resolve();
      };
      target.addEventListener(event, listener,
                              { once: true });
    });
  }

  function setAnimationTime(time) {
    document.getAnimations().forEach(a => a.currentTime = time);
  }

  promise_test(async t => {
    const eventType = location.search.substring(1);
    var box1 = document.getElementById('box1');
    var box2 = document.getElementById('box2');

    const promises = [];
    promises.push(eventPromise(box1, eventType, () => {
      box1.parentNode.removeChild(box1);
    }));
    promises.push(eventPromise(box2, eventType, () => {
      box2.style.display = 'none';
    }));

    await Promise.all(document.getAnimations().map(a => a.ready));

    promises.push(new Promise(resolve => {
      requestAnimationFrame(() => {
        // trip animationstart.
        setAnimationTime(6000000);
        requestAnimationFrame(() => {
          // trip animationiteration on any animations that are still running.
          setAnimationTime(16000000);
          resolve();
        });
      });
    }));

    await Promise.all(promises);

    // Garbage collection is best effort.
    if (window.garbageCollect) {
      await garbageCollect();
    }

    assert_equals(document.getAnimations().length, 0);
  }, 'Triggering the cancel of an animation during event handling does not ' +
     'crash.');

  </script>
</head>
</html>
